John Bolton in an interview on the Daily Show (6:15)
I don't think it necessarily follows that it's only the use of the nuclear weapon that really gives them the advantage. In the struggle within the Islamic world between Shia and Sunni many of the Arab states in the region fear not only Iran's continuing quest for nuclear weapons but their terrorist attacks against other Islamic regimes. Having that nuclear weapon would make a big difference. For example if Milosevic had had nuclear weapons as Yugoslavia was disintegrating Bosnia, Kosovo could have turned out very differently simply from the threat or the risk that he would use them
Stewart: (Interrupting) That we would not intervene if they had them
Exactly. That's why it's so critical to stop Iran from getting nuclear weapons. Once it actually has the capability the equation changes dramatically.
Now, moving from "nuclear weapons" to "capability" from one sentence to the next is standard for the US foreign policy community. Jon Stewart, of course, didn't catch it.
More important, Bolton says that a nuclear capability may have prevented the airstrikes and eventual regime change in Serbia. Bolton believes this would have been a terrible outcome. Avoiding US airstrikes and regime change probably does not strike the Iranians as such a nightmare scenario.
Bolton's admission that if Iran reaches the nuclear stature that Japan has, where it can credibly claim that in a crisis it has the ability to build a weapon, the US will not be able to accomplish or threaten with regime change is, by itself, reason enough to expect that Iran will not suspend enrichment or subject its nuclear capabilities in any way to any form of effective US veto.